Missiaen L, Lemaire F X, Parys J B, De Smedt H, Sienaert I, Casteels R
Laboratorium voor Fysiologie, K.U. Leuven Campus Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium.
Pflugers Arch. 1996 Jan;431(3):318-24. doi: 10.1007/BF02207268.
Intracellular Ca2+ signals in response to inositol 1,4,5-trisphosphate-producing agents often present themselves as Ca2+ oscillations and propagating Ca2+ waves originating at discrete initiation sites. We studied the spatial organization of the Ca2+ signal in single CPAE endothelial cells stimulated with adenosine triphosphate. The long, thin processes presented a higher agonist sensitivity and, for the same agonist concentration, a faster rise in cytoplasmic Ca2+ concentration and rate of wave propagation than the cell body. Ca2+ waves originated preferentially in one of these processes and then invaded the cell body. Removal of external Ca2+ induced a progressive inhibition up to blockade of the response in the process but not in the cell body. These findings suggest that CPAE cells contain many individual store units, each of which has the inherent ability to set the stage for Ca2+ release. A diffusing messenger originating from the initiation zone then coordinates the events leading to Ca2+ release in the individual store units to produce a Ca2+ wave.
对产生肌醇1,4,5 - 三磷酸的试剂作出反应时，细胞内的Ca2+信号常表现为Ca2+振荡以及从离散起始位点起源的Ca2+波传播。我们研究了用三磷酸腺苷刺激的单个CPAE内皮细胞中Ca2+信号的空间组织。细长的突起表现出更高的激动剂敏感性，并且在相同激动剂浓度下，与细胞体相比，细胞质Ca2+浓度上升更快且波传播速率更快。Ca2+波优先起源于其中一个突起，然后侵入细胞体。去除细胞外Ca2+会导致逐渐抑制，直至阻断突起中的反应，但不会阻断细胞体中的反应。这些发现表明CPAE细胞包含许多独立的储存单元，每个储存单元都具有引发Ca2+释放的内在能力。然后，源自起始区域的一种扩散信使协调导致各个储存单元中Ca2+释放的事件，以产生Ca2+波。
